One of the reasons why French ATC is nice to GA traffic is that, as part of their training at the Ecole Nationale de l'Aviation Civile (ENAC) in Toulouse, ATCOs can train for their PPL for free, then get 12 free flight hours per year. No doubt most of them take advantage of it, so when you talk to them, you are talking to a fellow pilot... Talk about perks!
Even though I'm from Paris, I only got to fly in France for hr-building before embarking on CPL. I found the overall experience second only to the US in terms of facilities, ATC, attitude to flying, rules, airspace, costs, and... fun!
Some airfields will conveniently "forget" your landing fees - particularly if you buy fuel. I doubt, however, that it will be the case in Nantes, a commercial airport with a number of Regional Airlines and charter flights.
Happy landings!